drivers: llcc: Write to sub-cache register based on version

Configure the write sub-cache register based on the version, as
it's not supported by older targets.

Change-Id: Ifc3f2d4d66612d6dcc6070d3cbc3fce97202ccf3
Signed-off-by: Rishabh Bhatnagar <rishabhb@codeaurora.org>
[rananta@codeaurora.org: Resolved trivial merge conflicts]
Signed-off-by: Raghavendra Rao Ananta <rananta@codeaurora.org>